Broad beans are an undemanding and valuable crop for all gardens. Probably originating in the Eastern Mediterranean and grown domestically since about 6,000BC, this plant was brought to Great Britain by the Romans.
Header image: a rich harvest of succulent broad beans for the table
Capable of tolerating most soil types and temperatures they provide successional fresh pickings from June to September. Early crops are grown from over-wintered sowings of cv Aquadulce. They are traditionally sown on All Souls Day on 2 November but milder autumns now cause too rapid germination and extension growth. Sowing is best now delayed until well into December. Juicy young broad bean seedlings offer pigeons a tasty winter snack, consequently protection with cloches or netting is vital insurance.
From late February onwards dwarf cultivars such as The Sutton or the more vigorous longer podded Meteor Vroma are used. Early cropping is promoted by growing the first batches of seedlings under protection in a glasshouse. Germinate the seed in propagating compost and grow the resultant seedlings until they have formed three to four prominent leaflets. Plant out into fertile, well-cultivated soil and protect with string or netting frameworks supported with bamboo canes to discourage bird damage.
Young broad bean plants supported by string and bamboo canes
More supporting layers will be required as the plants grow and mature. Later sowings are made directly into the vegetable garden. As the plants begin flowering remove the apical buds and about two to three leaves. This deters invasions by the black bean aphid (Aphis fabae). Winged aphids detect the lighter green of upper foliage of broad beans and navigate towards them!
Allow the pods ample time for swelling and the development of bean seeds of up to 2cm diameter before picking. Beware, however, of over-mature beans since these are flavourless and lack succulence. Broad beans have multiple benefits in the garden and for our diets. They are legumes and hence the roots enter mutually beneficial relationships with nitrogen fixing bacteria. These bacteria are naturally present in most soils. They capture atmospheric nitrogen, converting it into nitrates which the plant utilises for growth. In return, the bacteria gain sources of carbohydrates from photosynthesis.
Broad bean root carrying nodules formed around colonies of nitrogen fixing bacteria
Broad beans are pollinated by bees and other beneficial insects. They are good sources of pollen and nectar, encouraging biodiversity in the garden. Nutritionally, beans are high in protein, fibre, folate, Vitamin B and minerals such as manganese, phosphorus, magnesium and iron, therefore cultivating healthy living. Finally, they form extensive roots, improving soil structure, drainage and reserves of organic nitrogen. Truly gardeners’ friends!
Professor Geoff Dixon, author of Garden practices and their science (ISBN 978-1-138-20906-0) published by Routledge 2019.
We begin our new series breaking down key innovations in agriculture with the Haber-Bosch process, which enabled large-scale agriculture worldwide.
Ammonia – a compound of nitrogen and hydrogen – is therefore a key ingredient in fertilisers, allowing farmers to replenish the soil with nitrogen at will. As well as fertilisers, ammonia is used in pharmaceuticals, plastics, refrigerants, explosives, and in numerous industrial processes.
But how is it made? At the turn of the 20th Century, ammonia was mostly mined from deposits of niter (also known as saltpetre – the mineral form of potassium nitrate), but the known reserves would not satisfy predicted demands. Researchers had to find alternative sources.
Fritz Haber (left) and Carl Bosch (right) created and commercialised the process.
Atmospheric nitrogen, which makes up almost 80% of air, was the obvious feedstock – its supply, to all intents and purposes, being infinite. But reacting atmospheric nitrogen, which is exceptionally stable owing to its strong triple bonds, posed a challenge for chemists globally.
In 1905, German chemist Fritz Haber cracked the riddle of fixing nitrogen from air. Using high pressure and an iron catalyst, Haber was able to directly react nitrogen and hydrogen gas to create liquid ammonia.
His process was soon scaled up by BASF chemist and engineer Carl Bosch, becoming known as the Haber-Bosch process, and this would lead to the mass production of agricultural fertilisers and a phenomenal increase in the growth of crops for human consumption.
The Haber-Bosch process is conducted at a high pressure of 200 atmospheres and reaction temperatures of 450°C. It also requires a large feedstock of natural gas, and there is a global research and development effort to replace the process with a more sustainable alternative – just as the Haber-Bosch process replaced niter mining over a century ago.
In April, EU Members States voted for a near complete ban of the use of neonicotinoid insecticides – an extension to restrictions in place since 2013. The ban, which currently includes a usage ban for crops such as maize, wheat, barley, and oats, will be extended to include others like sugar beet. Use in greenhouses will not be affected.
Some studies have argued that neonicotinoids contribute to declining honeybee populations, while many other scientists and farmers argue that there is no significant field data to support this.
In response to the recent ban, SCI’s Pest Management Science journal has made a number of related papers free to access to better inform on the pros and cons of neonicotinoids.
Like to know more about neonicotinoids? Click the links below…
Robin Blake and Len Copping discuss the recent political actions on the use of neonicotinoids in agriculture, and the UK’s hazard-based approach following field research unsupportive of an outright ban on the insecticides.
Conflicting evidence on the effects of neonicotinoids on the honeybee population has beekeepers confused and has led to the increase in the use of older insecticides, reports one beekeeper.
Following the 2013 EU partial ban on neonicotinoids, experts called for good field data to fill knowledge gaps after questioning of the validity of the original laboratory research. To encourage future debate, realistic field data is essential to discouraging studies using overdoses that are not of environmental relevance.
This paper describes the consequences of the ban on neonicotinoid seed treatments on pest management in oilseed rape, including serious crop losses from cabbage stem flea beetles and aphids that have developed resistance to other insecticides.
The Research Articles
Particle size is one of the most important properties affecting the driftability and behaviour of dust particles scraped from pesticide dressed seeds during sowing. Different species showed variable dust particle size distribution and all three techniques were not able to describe the real-size distribution accurately.
Aside from particle size, drift of scraped seed particles during sowing is mainly affected by two other physical properties – particle shape and envelope density. The impact of these abraded seed particles on the environment is highly dependable on their active ingredient content. In this study, the envelope density and chemical content of dust abraded from seeds was determined as a function of particle size for six seed species.
Substantial honey bee colony losses have occurred periodically in the last decades, but the drivers for these losses are not fully understood. Under field conditions, bee colonies are not adversely affected by a long‐lasting exposure to sublethal concentrations of thiacloprid – a popular neonicotinoid. No indications were found that field‐realistic and higher doses exerted a biologically significant effect on colony performance.
Currently one of the least digitised industries in the world, the agricultural sector is fast becoming a hub of innovation in robotics. One report suggests the agricultural robotics industry will be worth £8.5bn by 2027.
Feeding the increasing global population – set to hit 8bn by 2023 – is a major concern in the sector, with farmers already stretched to capacity with current technology.
With this said, the European Commission – via Horizon 2020 – has launched a programme and fund to drive research and innovation in the area. Developments in precision agriculture, which uses data and technology for a more controlled approach to farming management, has been particularly encouraging.
But similar to other labour-intensive industries, such as manufacturing, robots could be used to relieve workers in difficult conditions, and there are many projects close to commercialisation.
One such project is SWEEPER – a greenhouse harvesting tool that can detect when sweet peppers are ready to harvest through sensors. SWEEPER runs between the vines on a rail and uses GPS tracking to navigate through its environment.
Although focusing on sweet peppers for this research, the group say that the technology could be applied to other fruits and crops.
The EU-funded consortium in charge of the development of the SWEEPER robot is made up of six academic and industry partners from four countries: Belgium, Sweden, Israel and the Netherlands, where the research is based.
Greenhouses pose harsh working conditions during harvesting season, including excessive heat, humidity, and long hours.
The SWEEPER robot in action. Video: WUR Glastuinbouw
‘The reduction in the labour force has put major pressure on the competitiveness of the European greenhouse sector,’ said Jos Balendonck, project coordinator from Wageningen University & Research, the Netherlands.
‘We hope to develop the technology that will prevent greenhouse food production from migrating out of Europe due to the 40 % expected rise in labour costs over the coming decade.’
Currently testing the second version of the robot, the research group already envision adding improvements – from sensors that can detect vitamin content, sweetness levels and the sweet pepper’s expected shelf life to the ability to alert farmers when crop disease could hit their crops in advance.
A world first
Meanwhile, engineers at Harper Adams University in Shropshire, UK, and agriculture firm Precision Decisions have become the first group to harvest a crop completely autonomously.
The Hands Free Hectare project – funded by Innovate UK – modified existing farming machinery to incorporate open-source data that would allow the control systems to be located externally.
At the start of the season, an autonomous tractor sows the crops into the soil using GPS positioning, and sprays them periodically with pesticides throughout their growth. A separate rover takes soil samples to analyse nutrient content and to check pH levels are maintained.
When the crops begin to sprout from the ground a drone is used to monitor growth by taking images. Finally, a combine harvester controlled from outside of the field harvests the crops.
Kit Franklin, an Agricultural Engineering lecturer at the university, said: ‘As a team, we believe there is now no technological barrier to automated field agriculture. This project gives us the opportunity to prove this and change current public perception.’
Image: Hands Free Hectare
Despite innovation in the area, farmers have been slow to embrace the new technology, partially due to the lack of high quality data available that would allow more flexibility in the sector. Others, including the wider public, worry that development will lead to job losses in the industry.
However, scientists say the jobs will still be there but farmers and agricultural workers will use their skills to control the autonomous systems from behind the scenes instead.
‘Automation will facilitate a sustainable system where multiple smaller, lighter machines will enter the field, minimising the level of compaction,’ said Franklin.
‘These small autonomous machines will in turn facilitate high resolution precision farming, where different areas of the field, and possibly even individual plants can be treated separately, optimising and potentially reducing inputs being used in field agriculture.’